This invention relates to a data output apparatus for taking all element data into a computer, editing them in the computer and transforming them into halftone dot images to be formed on printing plates in the step of producing image data to be used for making the printing plates.
More particularly, the present invention relates to a coded data output apparatus for producing coded data to be used for forming dot code images to a plate making apparatus, which by turn produces printing plates carrying dot code images to be printed on printing media to make the data in the images optically retrievable regardless of the type of data, be it audio data for voice and music, video data obtained by way of cameras and other pieces of video equipment or coded digital data produced by personal computers, word processors and other data processing apparatus. In short, a coded data output apparatus according to the invention is adapted to multimedia applications.
Conventional media for recording voice and music include magnetic tapes and optical discs. However, recorded copies in the form of tape cassettes and optical discs are considerably expensive and offered with high unit prices if recorded on a mass recording basis. Additionally, large space is typically required for storing tape cassettes and optical discs. Furthermore, the transport of such recording media is time consuming and costly by any means particularly when they are mailed or shipped to remote areas.
This is true not only for audio media but also for video media that carry video images produced by cameras and other pieces of video equipment and media that carry coded digital data obtained from computers and word processors. In short, the so-called multimedia flow of information faces this problem.
In an attempt to solve this problem, EP 0,670,555 Al (which corresponds to U.S. Ser. No. 08/407,018 filed by the assignee of the present invention) proposes a system for recording data in the form of a two-dimensional pattern of coded dots produced as a coded data image by two-dimensionally arranging a plurality of dots that can be transmitted by facsimile and reproduced into a large number of copies at low cost regardless of the type of data, be it audio data, video data or coded digital data to make it adapted to multimedia applications, and also a system for retrieving the data from the image.
According to the data format employed in the above system for coded dot data of two-dimensional patterns, a dot code pattern comprises a plurality of blocks arranged vertically and horizontally for two-dimensional arrangement and each of the blocks contains a marker, a block address and a data area for storing data for address error detection and error correction and actual data.
EP 0,7171,398 A2 (which corresponds to U.S. Ser. No. 08/571,776 filed by the assignee of the present invention) discloses a format for improving the density of recording coded dot data as will be described below by referring to FIG. 1 of the accompanying drawings. Referring to FIG. 1 and according to the above identified invention, pattern dots 278 are arranged between any adjacently located markers 174 in the first direction, while address dots 280 are arranged between any adjacently located markers 174 in the second direction. Each of the pattern dots 278 and address dots 280 has a size equal to that of a data dot 282 to be arranged in a data area 180. With such an arrangement for dot codes 170, the center of the marker 174 that provides a reference point for directionally determining the arrangement and reading data dots 282 can be identified easily and accurately by means of a set of pattern dots 278 having a predetermined pattern so that the original data can be retrieved without fail for multimedia applications.
Pattern dots, 278, address dots 280 and data dots 282 typically have a size of tens of several micrometers that may be 63 .mu.m for example, although the size may be reduced to several micrometers depending on the application. While a number of techniques have been proposed to enhance the quality of bar codes including Japanese Patent Application KOKAI Publication No. 5-15911 that discloses a technique of accurately detecting and controlling the inclination of a bar code printing head in order to prevent degradation in the printing quality that can be given rise to when an inclined head is used for printing and Japanese Patent Application KOKAI Publication No. 5-54165 that teaches a bar code printing method with a printer having a low resolution, no comparable techniques have been available for dot code printers that are required to print dot codes having a very fine dot arrangement with a very high level of positional accuracy.
On the other hand, the technique of desktop publishing (hereinafter referred to as DTP) for producing originals of documents and images prepared by computers for printing. The DTP output is examined for correction, if necessary, by means of a monitor and then directly printed on a film to produce a printing plate by means of an image setter.
Thus, DTP can be applied to the coded data output apparatus for producing coded data to be used for forming dot code images to a plate making apparatus, which by turn produces printing plates carrying dot code images to be printed on printing media to make the data in the images optically retrievable for multimedia applications if they are very finely drawn and the dots are required to show a very high degree of positional accuracy.
Referring to FIG. 2A, data to be coded into dots for multimedia applications are fed to a computer 102 by way of an input apparatus 100 and then the computer 102 transforms the data into image data by referring to the compression format, the error correction format, the dot code format and other reference data stored in an external memory 104 and transmits the image data to an image setter 106, which constitutes a printing plate preparing system along with a printing plate exposure apparatus 108. Subsequently, the printing plate preparing system prints a dot code image on a film, which is then exposed to light to make a printing plate. The produced printing plate is then put on a printing machine 110 to produce copies of a printed matter that carries dot codes.
Alternatively, a printing plate may be prepared without using a film as illustrated in FIG. 2B.
However, the above arrangement of preparing a printing plate cannot and should not simply use the DTP output because the configuration of dot codes have to be optimized for multimedia applications by taking the environment of handling dot codes into consideration, although the optimization of dot code configuration has not been discussed to date.